Fitting the lower rudder fairing to Vans scribe lines only gives about 1/8th clearance from the tailspring. Even though there should not be much deflection right at the root, I wasnt comfortable about it. I took another 1/4 " off at the forward end tapering to an 1/8th at the rear.
I made the first cut to the factory scride lines
It only gives about 1/8th clearance to the tailwheel spring
